Are your eyes red? Are they irritated and bloodshot?

Your optometrist should be the first person you see when you have red irritated eyes.

What is a red eye?

Your eyes become red when tiny blood vessels under the eye’s surface get larger, or become inflamed. This usually occurs when something is irritating your eye.

You may only have one red eye, or both can be affected.

Red eyes are often accompanied by pain, itchiness, a discharge from one or both eyes and your eyes may be swollen. You may also experience a change in your vision, such as blurred vision.

Often, a red eye can look worse than it feels.  However, if your eyes are red for more than a week, or if your vision is affected, or if there is pain, make an appointment with an optometrist.

What causes red eye?

There are many things that can cause a red eye.

It could be that you have been wearing contact lenses for too long, or staring at a computer screen for a long time without a break.

Red eyes can also be caused by allergies, blepharitis (inflamed eyelid), conjunctivitis (pink eye), dry eye, eye injury, or glaucoma.

Common causes of red eyes:


When pollen, pet dander, dust, or certain chemicals found in makeup or contact lens solutions get into a person’s eye or body, their immune system reacts. The body releases histamine to fight off the allergens, which also makes the blood vessels in your eyes get larger and your eyes can become red, watery, and itchy.

Dry eyes

When eyes do not produce enough tears, or produce tears that lack lipids, dry eye is the result.  Tears keep your eyes healthy and comfortable. Dry eye symptoms can include stinging or burning, lots of tears followed by periods of dryness, and sometimes a mucus discharge.

Dry eye can be painful, and your eyes may be red. Anyone can get dry eye, but its more common in women, especially those who have gone through menopause. As people age, they produce less of the lipid part of tears, which puts them at greater risk for dry eye.


Conjunctivitis happens when the membrane covering the insides of your eyelids and the white part of your eye, called the conjunctiva, becomes inflamed. It is a very common eye infection and children quite often experience this type of infection.

Conjunctivitis can be caused by allergies, bacteria or a virus. Viral eye infections, the most common, tend to improve on their own, and don’t require prescription medication. Bacterial eye infections require antibiotics. Both types of infection, are extremely contagious and spread easily.


When your eyelids are inflamed you may have blepharitis, it can cause your eyelids or eyes to appear red and swollen. Your eye/s may be burning, itchy, are sensitive to light, and you may have excessive tears.

Blepharitis can cause serious symptoms if not managed. It can lead to a loss of eyelashes, eyelashes that grow in the wrong location, or blurred vision. Blepharitis can occur if you have high amounts of bacteria on your eyelids, or the oil glands in your eyelids are clogged. In rare cases blepharitis can be caused by a mite.


Uveitis is inflammation of the middle part of your eye (the uvea). The uvea is between the white of your eye and your retina.

Symptoms include:

  • blurred vision
  • eye pain
  • eye floaters
  • sensitivity to light

Uveitis can be caused by:

  • autoimmune diseases, such as lupus, rheumatoid arthritis, and ulcerative colitis
  • infections, including syphilis, shingles, and toxoplasmosis
  • some types of cancers like lymphoma
  • the herpes simplex virus type 1

See your optometrist quickly as uveitis can lead to vision loss if not managed.

Subconjunctival haemorrhage

Sometimes, a blood vessel in your eye can break, leaking blood onto the surface of your eye – this is a subconjunctival haemorrhage. It may look serious, but it often goes away on its own in 1 to 2 weeks.  However, if you have a subconjunctival haemorrhage and your vision changes talk with your optometrist.

This condition can sometimes be caused by:

  • rubbing your eyes too hard
  • intense coughing or sneezing
  • vomiting
  • eye injury

You may be more prone to this condition if you’re taking blood thinners, or have diabetes, or hypertension.

Eyelid stye

A stye is a blockage of the meibomian gland that causes inflammation. It can affect the outside or inside of your eyelids.

If you have a stye, the edge of your eyelid can become red, swollen, and painful. This area may fill with meibum (due to the blocked gland) and can grow to the size of a pea.


A trauma or an injury to your eye can cause redness. Blood vessels in the eye open to allow more blood to get to the injury site for quicker healing. The open blood vessels are what cause your red eye.

Eye injuries can include scratches to the surface of your eye, puncture wounds, and chemical burns. These eye injuries need immediate medical attention and should be treated as a medical emergency.

Contact lenses

People who wear contact lenses touch their eyes more often which puts them at an increased risk of eye redness. The redness may be from:

  • scratches or scrapes on the cornea
  • eye allergies
  • eye infections
  • corneal ulcers – resulting from sleeping in contact lenses
  • dry eyes
  • giant papillary conjunctivitis – where bumps develop under your eyelid
  • contact lens induced acute red eye from wearing contacts overnight
Red Eyes can also be caused from:

Excessive alcohol use which reduces oxygen to red blood cells. This causes blood vessels to clump together and makes eyes appear red and bloodshot.

Smoking increases the risk of eye diseases that affect a person’s vision. Tobacco smoke is also a toxic eye irritant that can cause dry, red, and itchy eyes. Smoking marijuana also causes red, bloodshot eyes. An ingredient in marijuana causes the blood vessels in the eye to dilate, producing red eye that can last for hours or longer.

Whitening eye drops that claim to whiten eyes contain vasoconstrictors, or chemicals that shrink the blood vessels on the surface of the eye to reduce redness. The drops do get rid of red eye, but the fix is temporary. Many people who regularly use these types of eye drops build up a resistance to their whitening effects, which means that they will need to use more and more drops each time to achieve the same results.

How can red eye be prevented?
  • Don’t rub your eyes. Dirt and germs on your hands can cause even more redness and irritation.
  • Keep contact lenses clean, and do not wear them longer than recommended.
  • Remove eye makeup properly.
  • Take regular breaks when looking at the computer screen.

Make an appointment to have your eyes checked to make sure the cause of red eye is not something more serious.

Some eye conditions that don’t receive treatment, or timely treatment may result in permanent damage to your eye, which can lead to vision loss.

When should you contact an optometrist?

If your eyes are red make an appointment if:

  • your symptoms last longer than 1 week
  • your vision changes
  • you have pain in your eye
  • you become sensitive to light
  • you have discharge from one or both of your eyes
  • you take medications that thin your blood, such as heparin or warfarin

Your optometrist will determine the cause of your bloodshot eyes and provide you with the most effective treatment options.

Until you can see your optometrist, remove your contact lenses (if you wear them) and wear glasses instead. Bring your contacts to your appointment so your optometrist can evaluate whether your contact lenses are causing your red eyes.

Even though most causes of eye redness aren’t severe, seek emergency medical attention if:
  • your eye is red after trauma or injury
  • you have a headache and have blurry vision
  • you begin seeing white rings, or halos, around lights
  • you experience nausea and vomiting